Apparatus for testing fluid pressure switches



INVENTORS dad/EM 8 Sheets-Sheet I w W MA Oct. 28, 1952 F J ous'r EI'AL APPARATUS FOR TESTING PRESSURE SWITCHES Filed June 5, 1948 Oct. 28, 1952 F. J. FOUST ETAL APPARATUS FOR TESTING PRESSURE SWITCHES Filed June 5. 1948 8 Sheets$hee't 2 Jig. 2

Get. 28, 1952 F. J. FOUST ErAL APPARATUS FDR TESTING PRESSURE SWITCHES 8 Sheets-Sheet 3 Filed June 3. 1948 Oct. 28, 1952 F. J. FOUST EI'AL APPARATUS FOR TESTING PRESSURE SWITCHES 8 Sheets-Sheet 4 Filed June 3, 1948 INVENTORS /Am. 216/644 Max/4 1% M Oct. 28, 1952 F. J. F ousT ETAL 2,615,327

APPARATUS FOR TESTING PRESSURE swrrcmzs Filed June :5. 194a a Sheets-Sheet 5 'Jzy. 77

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IN VEN TORS Hum WW Q2 /0 .F. J. FOUST ETAL APPARATUS FOR TESTING PRESSURE SWITCHES Oct. 28, 1952 a Sheets-Shet '6 Filed June 3. 1948 J7 IZZLENTORSI A A nab a a. IIIIIIIIIIZ Oct. 28, 1952 F. J. FOUST ETAL APPARATUS FOR TESTING PRESSURE SWITCHES 8 Sheets-Sheet 7 Filed June 3. 1948 Oct. 28, 1952 F. J. FOUST ETAL 2,615,327

APPARATUS FOR TESTING PRESSURE SWITCHES Filed June a. 1948 s Sheets-Sheet s A, ill I 10/ I INVEN T0115 38] W. M M Y BY Maw Patented Oct. 28 1952 APPAHATUS'FOR'TE'STING FEUID PRESSURE; SWITGHESF Floyd J iFouSt,i-Dhn1 RandaIIZ BiirR; and, vRl'lpert C; Whelchel, Anderson, Ind., assig'norsto General Motors Corporation, Detroit,"M ich;, acor notation of Delaware,

Application June23;1,1948, Serial No; 30,945 8, Claims- (Cl. "7 -5- 1 j This. invention relates 515d ;-the vmanu-facture et stoptiight switches :which; arez-used in'ihydraulic, braking; systems to-, comp 1eter an: electric; circuit tov an findicatorulampi Whenthe, brakingggpressure is applied through: -the':sy stem= 1 An 7 object of the-invention is. the provision of; a machinewfow automatically testing; stop light.- switchesa; Thew machine: comprises a; conveyor having-g workho1ders--- for; receiving :stop:; light switcheswhich are movedby ther conveyor suecessiveiy; past a loadi-nggstationand. twoi'test-stations. At one test station, the switches arersub jejctedto a high pressure to" test for leak-stand are subjected to an electricalcircuit to testfor ground; At the secondtstation -tiiey; are subjected r to; low: pressurevto determine within. which; one-of a plurality: of pressurevrangesr thefixed-v contacts -1 of the -switch are: engaged by thGvDI-{GSSUIB acturz atedtmevabl'e contact: of the-switch;

Furtheraobjects andwadvantagesxof thepresentinvention'wvill bewapparent. fromthe; following;

description,v reference. being, had to? I the r: accom-rpanying: drawings wherein a, preferred embodi-- mentrof; thepresent invention sis clearly shown;

In thesdraw-ings:

Fig. i .1 is a side elevation of: the test machine; certain parts being shown vin. section.

Figs. 2-1 is a. view-*inv the. direction ,ofy arrow *2 of. Fig; -1.'

Fig, ,3-- is.,a. views in, thetdirection of arrow '13. :of? Fig. 2.

Fig;-. 4 is. aeviewv .in the -.-direction :of arrow -'4 of Fig.4"

Fig- .5 ,is a,,p1an:view of thermachinen Figs, 6uista-wiewvpartly in; section: onz'linewik-fiw of: Fig}; 1. r

Fig -f7 is, azf-ront eleizatiomof the high-pressuretest apparatus, this viewxbeing-in thetdirection ofiarrow 1 'ofFig. g5.

Fig.,8-is awsectionaiview on1.1ine:8r--8 of Fig-, 7.

Fig.; 8A=-is an; enlargement, :in section: of part" l38 of1:Fi ;8. v,

11 19.19 15a sectional; viewtonf line 9- 9:or Fig, 18.:

F58 10.=is.a front; elevationof-theiow pressure .testapparatus, thisiview': being-1 in the v die rection ,of arrow l of :Figa.

Fig 11 .',is'. atsectionalwview -onr liner 1 +44 ,of, Fig,

Eig., .12 is a. sectionalflvietw oneline, l2--l 2- of Fi'gL,.11";' I

Fig.1. 13",,is a plan.v view of. adevice for. cone. trolling; signal lamp actuating thyratrons. ac..- cording to the pressure required to, closejthe, switch under, test;

Fig. ,13A.is' a view in, the. direction.ofggarrow ]3A0Fi 13'...

Fig- .,,1'5 is ,a longitudinal sectional view of jm pre sure. lie device;

a Witch, ,SW4-

rig, .1'8, is', at. fra me t ry :view showingihe.

ppor Q 1 a1 Switch; SWil'T which isoperatei y ms mount d e r-t e" al-i Fi 1911s; an elevation ofn a devicefor eject5- mg, iIIomthe conveyor turmtable switches-which Fi s, 20;;and2tamseq ion v ws 9n the-mesport n it; 7

mg; 2351s a w rin ydia ram he i e ect ipa testing apparatus:

, R ferrineto Fi s. ,1 and. fzznater amp- L n 3 tachiedilto; p ates" 34' and 35 provide:- the framwszc tzo the mach ne: Agbrack'er 35- "ai tackled" to plate; E'T uppQrtSLa hou 1 vfor spe d. re u in -f e n t r ueli whi h :mOtOr 31$ ,dr'ives a shaft; j Shaft 39; drives at puliey' 40L (F nnected. by "a: belt BILWithJWPQH K 4! (Figs. 1 :and;12 .:atta he;d toe shai i tiou e' naieid bearings. 4' 44Iand; 45 r spr tiyelyt'seiz cured; to plates, 333'; 34 anidit35; he 1 se o the. housi gtr is attachedjtoibra k t j'bKSQ T W 36a; (Fi 4); pas neit r u h. o stfi 'iinigtne bra ket. By hif n mt e. u n i or zontall'm; the belt, 40a, isi'ntigl tened. Shaft; 42 driyes a gear wimeshing, with: a s m? atta hed to, a shaft 4B;I,iqu na.1ed:1in.. bearin s; nd v4.9a. at a e respectively to plates ,35Qandgj3i4; Shaft 48 ,op; erates a. Genev'a gear ,mechaniSm comprising; a p at 5ll; ,a o ler 5t ttach t m n l a lccking member 52 The roller 5.1, fingagfis ..radial slots 531m a. .drive n member sfilfliig, 6)- having, notches, 514, .which-,, Itec.e iYe the member 5 2S 1 which 1ocks..,the.- membe r;- '55vlagainst .,rotation when, not. being;driven;- lviiemb er,v 55 33, attached screws, 56' to, aihilbg i'l -wh ich. is attached; ,to, a shaft 58, journaled'in bearings 59 and 60 provided bygthe; plates -35 and-s33,. screws fiim fasten a rqtary conveyor ,or dial; 62; to the platwfit said screws;

video. adjustments-of the. dial, 6-2;, relative to the, Genevamgear driven member-55,; Plate-fiilflrFig 6) provides aecamwlob- 5131K h n a estthel roller 50b; of, switch SW1 to, cause-it to ,closesfor s ime when he, i'aL isnot bein d d-1- 'I'he shaft 42, drives a; 1 1 b, 'lfl gwhich screws, :I -I (Fi 5); .passing;through'earcu terslotselfi the 1y in; section; or; 1ine== 'e d sectional 1 VIEW" of; the" f relativeto the plate 92.

hub, fasten to a cam 73. Gem 73 engages a roller 74 pivotally supported by a bar 75 which slides in a horizontal groove provided by a bracket 76 and which is retained therein by a cover 77 fastened by screws 78 to the bracket. A screw 79 attaches the bar 75 to a bar 80 which pivotally supports fingers BI, each having an inclined surface 82 as shown in Fig. 1. Springs 83, attached to the bar 83 and to studs 84 fixed to a plate 85 attached to the bracket 76, urge the roller 74 against the cam 73. The plate 85 carrie normally closed switches SWI ll and SWI I (Fig. 1) whose actuating rollers 36 are engaged by a pin 87 carried by cam 73. Switches SWIG and SWII are momentarily opened at the end of the tests. 7

Each finger SI is engaged by a roller 30 (Fig. 1) supported by a screw 3I passing through a plate 52. The screw 3I receives nuts 93 and 34 by which the screw 3| may beadjusted vertically Since there are two rollers 30, one for each finger 8!. there will be two plates 32 (Fig. 2). These plates are attached respectively to the plates 35 and 3| and to plates 35 attached to plate 33 (Fig. 1).

The apparatus at th high pressure test station will now be described with reference to Figs. '7, 8 and 9. A bushing I (Fig. 1) guides a vertically movable rod I3I having a notch I32 for receiving one of the fingers BI which engages not only a roller 93 but also a roller I33 pivotally supported by the rod I M. Rod IBI is integral with a frame or head I34 carrying studs I which springs I06 (Fig. 1) connect with-screws 537 carried by a plate 92. Screws I37 receive nuts I38 by which the screws are vertically adjusted. By this means the roller I33 is kept in engagement with the finger 8| andthe finger 8! in engagement with the roller 93.

The head I34 supports a non-conducting block Imfixed by screws III and supporting tubes I i2 through each of which there passes a rod I I3 providing a contact II4 for engaging one of the terminals t of. a stop light switch S,'indicated in dot and dash lines. A spring II5 normally urges the contact down until a' nut or collar H5 attached to the upper end .of'the rod II3, engages the upper end of the tube I I2. Screws I i8 fasten to the block I Ill a non-conducting plate I I 3 having'notches I therein. ,Through one of these notches thereprojects a terminal post I2! attached to the collar H6 and a screw I22 secures a lead wire I23 to this post. Screws I24 secure to the frame I54. a bracket I25 carrying a switch SW6 whose operating roller I25 engages the collar I I6. When contact II4 engages a switch terminal t, downward motion of rod H3 and collar H6 ceases. As the head I04 moves down after this engagement. roller I 23 rides on collar IIB and causes switch SW6 to close. The parts I34a and IE4?) of frame I34 are cylindrical and are threadedly engaged by a nut I27 which secures a ring I28 through which the switch S extends, said ring retaining the switch S upon a workholder.

Switch S is supported by one of the six work holders .IBD which screws I3I attach to the dial 52. Switch S (Fig. 22) comprises a housing h, containing a metal disc dI, an insulating disc (Z2 and a metal diaphragm d3 which serves as a movable switch contact to engage the ends of terminals t, which are supported by insulating block b. Each time the dial is indexed, a switch S is placed in alignment with therring I28 and with a nozzle I32 which a nut I33 secures to a cylinder I34 which receives a plunger I35 carrying a check valve comprising a ball check valve I36 in a cage I37 and retained by an apertured plug I38. The check valve is in communication with a hole I39 in the plunger I35 which is in communication with a pipe tapped opening I40 to which a flexible pipe can be attached to make connection with a source of compressed air. Thereare passages I 4! and I4Ia communicating respectively with the cylinder bore and with pipe tapped openings I42 and M211 to which devices 2H) and 223 (Fig. ,3) to be described are respectively attached.

During operation of the machine air pressure is continuously applied to the cylinder I34. When nozzle I32 does not engage a switch S the ball I35 rises against the lower end of plug I33 which has narrow radial grooves I38a (Fig. 8A) through which air can pass to the nozzle. When the nozzle engages a switch S, pressure builds up above the ball; and, when the pressure becomes sufiicient, the ball I35 moves away from the plug I38 to allow air to pass directly through the control hole in the plug; The escape of air from the nozzle is not excessive because the timeduring which the switch S is engaged by the nozzle-substantially exceeds the time during which the nozzle is not engaging the switch S. The foregoing applies to the control of air flow from cylinder I34 (Fig. 11) at the lowpressure test station.

The plunger I35 slides through packing I45 (retained by a packing gland I45 threaded into the cylinder I34) and'passes through a plate I 47 supporting threaded rods I48 which pass through brackets M3 and which receive nuts I53 by which the brackets can be adjusted relative to the rods I43. Screws I5I secure the brackets I43 to bars I52 which screws I53 attach to a block I54 welded to cylinder I34. A block I55, welded-to cylinder I34, receives a shaft I56 to which eccentrically located screws I57 (Fig. 9)

attach the bars I52. Block E55 has a notch I58 rendering accessible a hole I53 in the shaft I56 for receiving a rod by which the shaft can be turned in order to efiect movement of the cylinder i34 relative to the bars I52 and plate I47. The shaft I55 is locked in the desired position of adjustment by a set screw I63 threaded through the block 55. In this manner the cylinder I34 can be secured in the desired position of adjustment with respect to the plate I47 which'normally rests upon a bushing I55 (Fig. 1) which screws I33 attach to the plate 35. Therefore the distance from the nozzle in its lower position to the switch S can be adjusted. Bushing I55 provides a guide for the vertical movement of the plunger I35. The plunger I35-is pivotally connected at its lower end with a pair of toggle links I (Fig. 2) pivotally connected at I7I with a pair of toggle links I72 and a clevis I73 connected with a piston rod I74 of a compressed air servo-motor having a cylinder I75 pivoted at I75 on a bracket I77 attached to a plate I78 supported by the plate 35. Links-I72 are connected with a clevis 733 attached to a screw IBI passing through a bar I82 attached to plate 33 and to a plate I83 attached to plate 35. Nuts I84 threaded on the screw IBi provided for vertical adjustment of the latter relative to the plate I 82. When the piston rod I74 moves right (Fig. 2), the plunger I35 moves up to cause, through a spring H38, upward movement of the cylinder I34 to cause the nozzle I32 to engage the switch S being tested, while at the same time, the rod IBI has ezer szana beerrmoved down to cause contact *1 m to ensaise a switch terminal t.' when" the piston rod I14 moves'left the plunger I35 movesdown. "Before the cylinder- I34 moves permitted to expand to hold thc'nozzle I32again'st the switch S while the plunger I35 is moving down to" cause its shoulder I89=to engage the plate I41. Then the" plunger I35 and the-plate I41 and 'thecylihder 'I34 'move down -to'geth'eri' Lubricant is fed into the air Whi'clris'f"caused. to enter the cylinder I34 at I4Il'. Liib'ricant'which escapes. from the nozzle I 32 will be received by a groove I90 in the nut I33-and wilt-gravitate? through ahole I91 and then" down around the: cylinder'l 3'4 into'a'trough I 92 hav'inga-discharge pip I93 connected with a suitabljvessel (not: shown)'.' I

The" apparatus in" the low" pressuref'istation" which is shown in Figs: 10, ll and" 12; 1s con struct'e'd like" the apparatus "describe'dwith refer=- ence to Figs; 7;"8and 9"and*'the -partswhich are' similarare designated loy-thesame*numhers with down the spring- I-88 is the'prime'aflixed' to each 'number:-- The-hitter I ences between thetwo'appa'ratuses areas; follows;

Onlyoneofthe contacts ll4 of the-head" I04 at" the high pressure test station is connected with a' wire, such" as I23"; but; as-to the head I04" at the low pressure-test station; boththe contacts II4" and I I4a arecon'nec'te'd with-wires such as-I23v'. Therefore thereare two terminal posts I2'I attached respectively to two" collars 6' attached to two'rod's'I I3 carryinjg'two'con tacts I I4 respectively"forengaging"both termi nals of the switch S as shown inFig-L' O'ne'fof the: collars" H6 is engaged by-a'roller I26? of a SWltCh'SWE (Fig. '11). 'Ihebrackets I49" (Fig; 10) are'directly' attached to the cylinder I34"! The distance between cylinder I34; and plate I4-l'is'adjusted only by the screws I50 threaded on'th'e rods I49' extendin'g from plate-I41. Re= ferring to Figs. 1'and'2the plunger I35 is conthe -case'of the pressure gauge2Illj Screws 216 threaded "through the bracket can'be' adj'usted to' contact theperiphery' of the gauge in order to adjust the distance of the plunger "relative *to thecenter of the gauge.

A pressure relief 'valve 220 (Fig. 15) is con-- nected with the cylinder I34 by screwing it into apipe tapped opening I 42a (Fig. '7) Alow pressure gauge 230 (Fig; '2') is connected "by an L23I,

valve 232, pipe-233, screwed into a pipe --tappedv opening I42'a" connected by a holI'Mawith the, bore-of the cylinder I34; Thethreaddopenifig I42 receivesa'pipe240 (Figs. 13' and 14*)integral with a nut 241" threaded on'a cylinder 242 which receives a piston "243 having-a rod 244 'wh'ich' a screw2'45 attaches to a collar-"2'46 fiked'to aplate 24? carrying set-screws 248, 249 and 250 thre'aded throughthe'plate" 241 and retained in the-desired position'of'" adjustment bylock nuts 25'I'. -The screws 248; 2'49and' 25Ilare in alignment resp'ec tiyel'y with the plungers258 2'59 and" 260* ofswitches SWI SW2 and SW3 which are mounted on a plate =2 52 attached torods '2 53 which are v r 6 suriaqrtecbwtrackets z sa attachmfto thcyifii deem; "screwsare adjustedWd iiierent:

- distances from the switch plilng'er's sothat the switches are operated in succession depending on" the extent of *movement" to the: left of 'the pis'ton 2-43 against theaction of 'asprihg 26I which is retained. by anut 26! threadedly "engagingthe left end of'the- 'cylinder 242$ Asthe, pressure flui'dapplied through the nozzl'e 32- f cessively closed and the numberof swit'ehe w err will close' 'is determined by-the" extent 0f" r'i'se or ressure In a mariner 'to'' he -descr'ib'ed,-' these switches control lamps whieh" iiidi'cate whetlfer i or' not the pressure has 'reache'd certain vmuesg The dial 62 (Fig. 6) carries six earn plates 216 each for ehg 'sin'g the "r'oller '21 I (Fl 183 02 a switch SVIFI 2" supported by -bracket ifl supports o. be described; during the indexing ofthe "dial a" I solenoid SOI3 (Fig: l9) iscau'sedtobe nergiiee if' swit'ch S4-is0peril' Whemsolehdid" s13 sexier-- gized; ltfefi'ects the opening-of avalye-28I sup ported by "a plate 2 82" attached to -ap1ate 283 attached to plate)? (Fig. 19 Compressed air isadmitted toapipei2B4 -Which 'blows 'th witch" sf upwardlyiromthe workholiier'l was auses it tostrike againsta'hood sandwich-descend through a" chute- 286* extending'into'a pipe-1'81" ahd into a bin 288- closed by 'a-cover' 2 89 1 which supportsthelpipe: 281, Thechute' 2flfi is 'sup ported by'a bracket "290"which" screws 2"9I attach" toplate 39. 1 Pipe 2 a4 'is supported near'its' upper end 'bybeingplainped' between two b1ocks292 and 293 secured Icy-screws 294.- Screws'2'95 fi'x"to-' the plate 30-. Referring to-Fig. 23; 1 10" V: A; C1 'wiresiiflllf? G1 are connected throughjunctions I :ahd 2 with primaries 303- and anrof'transrormers TfanaTz. Secondary 355 through rectifier tube v l' rmdd'e'i and V5 (each model CD3) supply; through'j uhc tion '3; switch SWI 0 and junction" 4; voltage'to" the plates of-Thyratrons II II-{Ilffand '('achmodeF 2050) Secondary "3 06 supplies I cathode heater" current fortubeVI. Secondary" 30'! provides cathodeheatercurrehtat' x for-the Thyratrons. Choke T5- and condenser CI*provide'-a masts divert-ripples to ground. I

Transformer T2 with seleniumrectifierSRlI provides normal negative grid bias for the Thyratrons. The bias is slightly'morenegatiyethan' required to prevent the Thyr'atronsfrom' conducting.- I 1 Condenser C2 grounds ripples from--I'hyra'- tron grid bias. Condenser-"C3 grounds ripples from 'Ihyr'atronplate"supply:

Switches SW l, SW2, SW3 (Figs. 2, '13 23 which normally engage contacts C,- moye 'to c'ontacts 0 when the pressure on the diaphragm I of the switch under test at' statio'n 2 (l'ow -pressurestest) reaches '45 lbs, lbs; 1bS: ;-X-'espectively." Y z:

Switch SW4 on gauge ":2 to:(Figss IG-lfiith nor-f many open; andit 'closes' iwhen the :tgaugecshows" comes down to engage the switch acreage,

SwitchySW5 ,-:on :the low pressure head (Fig.

11):- is normally open; and it closes when the head under test and to make contactwith its terminals. v

Switch SW6 on the high pressure head (Fig. 8) is normallyopenyand it closes when the head comes down to engage the switch under. test and to; make contact with one of its terminals.

Switch SWl isa normally open switch which i closed at the end of indexing and is allowed to openyduring-indexing. I

@Solenoid S08 when valve to open to 'admit compressed air to the lower end of cylinder '202 (Fig. 2); which causes nozzle-.132 (Fig.'l2 )-to engage the switch under test... :r

Solehtid-LSOS whe n energized causes an air valve to -opento admit compressed air to the left end of cylinder I75 (Fig. 2) whichcauses nozzle l- 32-to engage the switch under test. Solenoid S09 (-Fig. 3) issupported by a bracket 500 attached to theservo cylinder I15. Solenoid S09 has a l-armature 50!, (movable right when the solenoid. isenergized) connected by pin 502and link 503.with a lever 504. pivoted at 505 on a.-

bracket 505.carriedby the member 50iextending from the-left head of cylinder I15. Member 501 contains a valve having an operating rod 508 engageable by the lever 504. When armature 50! moves right compressedair flows from hose. 509 through the open valve and into the left end of cylinder H5. ,,The control of air flow into the bottom. of cylinder 202 of the low pressure testing apparatus by solenoid S08 is identical with.

that described with respect to the control of air flow intothe left end of cylinder I15. In Fig. 1 the parts actuated by solenoid S08 are marked withthe members applied to corresponding parts operatedby solenoid S09 (Fig. 2) with primes affixed. When the solenoids S03 and S09 are deenergized, the valves are returned by springs to normal status in which flow from the compressed air source to the servo cylinders is blocked and these cylinders are vented so that springs therein return the servo rods 20! and ll lrespectively to normalposition and cause the nozzle I32 and [32, respectively to move down.

Switches SW10 and SW are normally closed and are opened momentarily just before the end of the cycle after tests are completed and before indexing starts.

' fswitchswlz, operated by cam plates ricear ried by the dial 62 (Fig. 16), is normally closed. It opens when an index is about half completed.

Solenoid S013 when energized opens valve 28| (Fig. 17) to cause compressed air to fiow from pipe284 to eject, duringindexing, from station I to station 2, a switch which does not test 2500 lbs. or greater.

' Relay REI has a coil 3l0 and normally closed contacts 31 land 3l2.

RelayREZ has a coil 320 and normallyclosed contacts 32l and 322. Wire 3|3 connects con tacts-:3 l2 and 32 I.

Relay RES has a coil 330 and normally closed contacts 33l and 332 connected by wire 333- with junction I4. I I

.Relay RE4 has a coil 340 and normally open contacts! and 342. I

Relay REhas a 0011.350 and normally open contacts 35! and 3.52 and normally closed contacts 354, and 355. Wire 333 connects332 and 352. -Wire 353 connects contacts 3M, .35]; and 354 with .wire 365 connected with wire 30L Belay REG has a coil 360 and normallyopen energized causes an air contacts 361' and i362, andnormall'y open con tacts 363 and-364. v Wire-365 is connectedto 362 and 364. Wire 365 connects wire 302 with coil 340 and solenoid Sl3 connected through switch Sl2 with wire 353 connected with contact .354. v

Relay RE! has a coil 310 connected with the secondary of transfer T4 and with a contact ofv the switch under test. vRelay RE! has normally I Contact 3' is connected with wire 365. Contact 312 is connected open contacts 3' and 312.

by wire 313 with coil 360 and contact 36L Switches SW6 and SW! connect wires 38I and 382respectively (connected with wires and 302 respectively) with wires 303 and 384 respece tivelyconnected with the ends of solenoid S00 and with the primary of transformer T l. Switch SW5connects wire 38| with solenoid Sil connected with wire 384. At the end of indexing, switch SW1 is closed, and, when the switch under test is engaged by theqhigh pressure head at station #I, switch SW8 closes and solenoid S00 is energized and the cylinder I34. is raised and pressure oil above 2,000 p. s. i. is applied. If there is no-ground in theswitch S and the switch S not pass the high pressure leak test, switch SW4 would remain open and relays RE i and REE would not operate and solenoid S013 would receive current. when switch SWIZ closes through wire 366 andwire 356, contacts 355, 354 and wires 353 and 365. The switch S would be blown-out at about half-way of the following index.

If the switch S passes the high pressure leak test switch SW4 closes and relays BB4 and REE both operate and the circuit o f-solenoid S013 is interrupted during indexing at 354 separated from355. I 1

During indexing, switch SW7 opens to deenergizethe solenoids S08 and S09. During the lat ter part of indexingswitch SWi2' opens to deenergizable solenoid SOI3; After the high pressure test, switch SW4; will open if it hadbeen closed and coil340 of relay REG will be deenergized. Near the end of the cycle of operation,-

switch SWH opens momentarily to disconnect wire 302 from relay coil 360 and relay coil 350 so that relays RES and BE5 returnv to normal status. If relay RE? had been'energized, it returns to normal status when the high pressure test head rises to disconnect coil 3'50 from a grounded contact of the switch. I

At the high pressure test station, it is immaterial which terminal of theswitch S is engaged by contact H4 (Figs. 5, t) since the test is to determine whether the switch diaphragm (is (Fig. 22) which under air pressure bridges the terminals, is grounded on the metal switch case. Under the high pressure, test, the diaphragm is stressed not only to make contact with adjacent switch contacts but also to stress the peripheral insulation which should withstand the pressure.

If it does not, the diaphragm may be grounded. A ground might not showup under normal oper: ating pressure. But under abnormal operating pressure, a ground might occurwhich would give xtroubleinservice. Hence the .high pressure test .is under .a pressure which would-exceedany ab- ;normal pressure which might be encountered later whenithe switch .S-isused in a hydraulic brake-system.

"If theswitch S passes. the leak test and the ground test atthefirst station. it passes .to the second-station where. it is subjected to. air pres- ;surerto .determinein what-range of pressurethe diaphragmof the switch bridges its contacts.

.-:After. the -switch 'S-arrives at the second station,.the head 1.0! descends andboth terminals wswitchsswicloses. solenoid S08 is energized,

cylinder .134 risesland. the nozzle 1.3.2'isapp1ied.

ate the switch. .If' the switch diaphragm bridges the-contacts of the switch before the pressure buildsupto-AS p. .s. i. .only the yellow lampLl will'burn. ,If the switch closing pressure isabove 5.,p. s. andgunder 100p. s. i., only the green lampLZ- willqbu-rn. If. the switch closing pressure .is-about .100 p. s. Land under 125 1).; s. i.,,on1y blue lamp-L3 will burn. If the switch closin pressure isabove. 1-2-5 p: s.-,i., only the white lamp L4 will burn. .These lamps-indicate.theclassification of switches. S-according-to contact closing pressure trainee...

,of the-switchare connected. into ,thetest. circuit.

. i110 wire 1.402,. contactsof relays RE3, REZ, .RE I, .to ground. [.Tube .IVpasses vcurrentto white lamp LA. .No other .Thyratroncan pass current. .because .none of theswitches. SW 1, SW2 SW3. are-.at

I After the. test. atstation 2., the head 104.15 raised-and the cylinder I34 .is;lowered.and indexing .to, the loading. station takes place, switch that. the.hydraulicallygoperated switch... is tested first at,..a high .pr essureand ground .test'station where it is tested for leaksoi operatedpressure fluid...and foragrounded diaphragm. .If it. fails tc-.pass..,either.test, .it..-is ejected from its workholder moved by-a...conveyor dial- If the switch passestheleaktest andthe ground test, it passes to.-.-a secondstation whereby the'burning of one i only .of. aseries. of lamps, of. difierent colors; the

gIf.theaswitch-clesinspressure.isunder45 p..s. 1.,

.SWiteh-SWt remains closed at the time the switch under test-isclosed. At-that time RHl of tube TI; is'.-shortedoutby the following circuit: .lower end. of-RB;wire-WMSWI, 41H switch under test closed; 402:.and-contactsbf relays REG, REZ, RE! to:groi nd. j'Negative grid-bias is reduced and tube, I-.-condu c;ts.-.current-to lamp Ll-and coil 3,!!! ofrsrelay REl..--C.ontacts 3H and 312 separateqand 11010131161 Thyratron willconductalthough other switches SW2,;SW3 mayzbe closed-after the switch cunderatest closes-contact.

.zt-Ifi-the switch closing pressure is over45 p. s. i. and under 100 p.-.s. i., switch SW I will be at O and switch SW2 will be at C. Nothing happened 'when SWl moved to 0 because the switch S -:undertest had not yet been closed. Tube I does not. become conducting'when the switch S closed :becauseswitch SW1 is not at C but is at 0. Tube II becomes conducting because its negative grid biasis redueedsi-nce R! l of II is shorted by the following? circuit: lower end of R1, wire 4H3,

' switch :SW2 at C, switch SWI at O, wiredlll,

switch-S; wire 492, contacts of relays REB, REZ, RE! to: ground. Tube II passescurrentto green lamp-L2 and -t0=r00i1i132-0 of RE? which prevents tubes :III and IV -:frem becomingconducting althou lrzthe pressure rises above 125 p. s. i. after 'testedrswitchiSccloses.

ilfitheswitchpclosing pressureis above. 10.0 p. s. i. andmnderl; ps5. i. when tested switch S closes, tubesfiI and "lIrcannot conduct because switches SWlwandSWZ are at -O while switch SW3 iseti Resistance .R,l;2-oftube III is shorted by thejfollowing circuit: :lowerend ofRB, wire ,SWI13'C'115SW3' :at C; switch SW2 a-t 0,;switch TYSWI- :atuQ, wire. 4.9.1, tested switch S, wire M2, "contacts of relays RES, R1512; RE! toqground. Negativeggrid bias is reduced on tube .111 which passes current to blue lamp L3 and to coil 33!! of relayRE3. This prevents tube IV fromconductinggalthough pressure may rise above 125 .p-.:s.1i-. aftertested switch S closed.

If the switch closing pressure is above 125 ms: i.,,;switche.s:.S,W I, SW2-.;$W3 are. all at -O--. menisci tub av. isashorted by the renewin circpitz; lower end:.;0.-f. 1R9, -wire- -.ll4,-'switehes ,sWl sw2il-fiwhat -.+-.O.-, wire flll l, tested switchS,

contact closing. pressure range of the SWitCh'iS indicated...'Eor.example:

v "Gontact'GIOsingPressure After :the test at the second :sta-tion the dial moves the switch to a. loading station where .the operatonremoves: itzand places it. in-theproper bin chute. which :oneqofi .the lamps ,had indicated. Although";the.';lamp goes out .beforeindexing the dia.l,itx.is .easy for the operator to remember which lamp .had ;been "burning. -Beforeithe; next test .atxrther, second. station-;can' result in the burning of :a lamp, there "alapse of time during which-.thehead .H!4. "1c1omes down to make con- :tact' with theiswitchas to be tested and to close xswitch. Eritif av switch in the Workholder under the :head) :and'. to cause the solenoid S08. to beenergized and tocause thecylinder I34 to rise and .airpressure to. be built u'p'against the dia- --phragm .ofswitch :Szand to cause the switchdiaphragm'zto rengageathe switch contacts and the pressure-ratwhichqcontact is :made to be'indicated -'by.".i1'ihe; ciosingaof, noneiof,..or by the closing of onezor more? of switches-Swi 'SWZ. SW3. .,;Be-. 'foretheswitch:Ssis: closeobmo lamp burns. By the; time .zaz'lampsiburnsuagain the operator will have. 'removeditherswitch- S previously tested.

whileszflle'embodiment of the present inventionras. herein .d-isclosed, constitutes a preferred formyit .-is "to..:be understood that other forms might/be adopted,;.a=ll:.comi-ng within thesc'o-pe tithe claims which follow.

*Whatzis claimed-is.as-followsz I I 1. A,machineiortestin Switches having fixed contacts and a; movable contact actuated into engagement with the fixed contacts by fluid pressure and. having-a pressure, fluid chamber witha pressurefluid, inlet and having terminals extending from: aside thereof, said machine comprising-pa rotatable .dial,..a- .pluralityof workholders-carried.thereby each adapted .to receive a. switch to be tested, means'for-indexing the ;dial trom. a-loa'ding station to; a high pressure test. station landnto -a-..1low pressure teststation,

similar: apparatus-1 ateach test: station, each h p? a l e 11 side of the switch to be tested and movable into and out of engagement with the switch,means carried by the head for making'an electrical connection with the switch when the head is advanced thereto, a member movable toward and away from the opposite side of the switch for making connection therewith for flow of pressure fluid into the pressure chamber of the switch, means for moving the head while the dial is stationary, a mechanism for operating. the dial indexing means and the head moving means in recurrent sequence, means responsive to movement of the head to engage the switch for causing themember to make fluid connection with the switch and, means responsive to the establishment of said fluid connection for causing fluid to flow underpressure into thepressure chamber of the switch, an electrical device having terminals connected by the head at the high pressur test station with the tested switch terminals and having means for detecting leakage of the tested switch when subjected to high pressure, and an elec- I trical device having terminals connected by the head at the low pressure test station with the tested switch terminals having means for determining in which one of a plurality of pressure ranges the contacts of the tested switch close.

'2. A machine for testing switches having fixed contacts and a movable contact actuated into engagement with the fixed contacts by pressure and having a fluid pressure fluid chamber with a pressure fluid inlet and having terminals extendin from a side thereof, said machine comprising a rotatable dial, a plurality of workholders carried thereby each adapted to receive a switch to be tested, means for indexing the dial from a loading station to a high pressure test station and toa low pressure test station, similar apparatus at each test station, each apparatus comprising a head adjacent the terminal side of the switch to be-tested and movable into and out of engagement with the switch, means carried by the head for making electrical connections with the fixed contacts of the switch when the head is advanced thereto, a cylinder movable toward and away from the opposite side of the switch, a nozzle carried thereby for making fluid connection with the pressure fluid inlet of the switch, a piston in the cylinder and having connection with a fluid pressure source and a duct in the piston leading from said connection into the cylinder and including a passage through a notched valve seat, a check valve urged against said seat by fluid pressure from said connection whereby escape of pressure fluid from the nozzle is restricted when the latter is not engaging the switch, means for movin the piston toward the switch, a spring for transmitting movement from the piston to the cylinder to initiallypress the nozzle against the switch whereby, as pressure builds up initially in the switch, the check valve is forced from its seat and the duct in the piston is unblocked and increased pressure is applied'to the switch while the nozzle is being urged by increased fluid pressure against the switch due to pressure increase in the cylinder, means for moving the head while the dial is stationary, a mechanism for operating the dial indexing means and the'head moving means in recurrent sequence, means responsive to movement of the head to engage the switch for caus i ing the piston to move toward the switch, an electrical device having terminals connected by the head at the high pressure test station with "the tested switch terminals and having means for detecting leakage of the tested switch when subjected to high pressure, and an electrical device having terminals connected by the head at the low pressure test station with the tested switch terminals having means for determining in which one of a plurality of pressure ranges the contacts of the tested switch close.

3. A machine for testing switches having'fixed contacts and a movable contact actuated into engagement with the fixed contacts by fluid pressure and having a pressure fluid chamber with a pressure fluid inlet, said machine comprising a rotatabledial, a plurality of workholderscarried thereby each adapted to receive a switch to be tested, means for indexing the dial from a loading station to a test station, means at the test station for applying pressure fluid to the switch, means at the test station for making an electrical connection with a switch fixed contact, means capable of ejecting the switch as it moves from the test station, a solenoid for controlling operation of the ejecting means, a current source, a circuit for connecting the solenoid with'the source including a switch closed durin indexing and, in parallel, a normally closed switch and a normally open switch, a second circuit including a current source, a magnet coil and the connection to a fixed contact of the switch being tested, said magnet coil being energized if the movable contact of the tested switch is grounded, means responsive to energization of the magnet coil for closing the normallyope'n switch in the first circuit, a third circuit including a second magnet coil and-a switch for connecting it with thefcurrent source first meritioned, means responsive to attainment of a certain fluid pressure in the tested switch for closing the switch in the third circuit to energize the second magnet coil, and means responsive to energization of the second magnet coil for opening the normally closed switch in the first circuit. k

i. A machine for testing switches having fixed contacts and a movable contact actuated" into engagement with the fixed contacts'by fiuid pressure and having a; pressure fluid chamber with a pressure fluid inlet, said machine comprising a workholder for receiving the switch,

means for applying fiuid pressure to the switch to cause the movableco'ntact to engage the fixed contacts, a current source, a plurality of indicators, a plurality of devices respectively for connecting the indicators with the source, a twoway switch having a normal or first circuit making position and a second circuitmakingposition, means responsive to the attainment of a certain pressure applied to the tested switch for causing the two-way switch to move to second position, a first control circuit completed by closure of the tested switch while the two-way switch is in first position, means rendered operative by completion of the first control circuit for rendering operative the device of the first indicator, means responsive to operation of the first device for preventing operation of the second device when the two-way switch moves to second position and a second control circuit completed by closure of the tested switch while the two-way switch is in second position for rendering operative the device of the second indicator. I

5. A machine for testing switches having fixed contacts and a movable contact actuated into engagementwiththe fixed contacts by fluidpres sure and having a pressure fluid chamber-with a pressurefiuid inlet, said? machine-"comprising aworkholder for receiving: the switch means {for applying-fluid pressure to-theswi tch to cause the movable contact to engage *thefixed'contacts,

a current source, a plurality orindicatoraaa -plu r'ali-ty of Thy-ratrcns respectivelyforconnecting the-indicators with 'the'source, and each having -a grid normally' negatively biased suiiicientlyrto prevent conduction by the Thyratron; :atwoeway switch having a normal or first circuit making position and-a secondci'rcuit making position,

meansresponsive'to-theattainment of a certain pressureap'plied to the-tested switch for causing the two-way switch to move to second position,

' a first control--crrcuit completed--by closure of the tested switch whi-lezthe:tworwaytswitchris im'first position for d creasing the negative bias m the first Thyratron, grid whereby therfirst Thyratron become conducting, a relay rendered operative whenthe, first Thyratron is-ccnducting. forprethe two-wayswitchmoves/to second position; and

a ,secondcontrol circuit completed by closure-of "the tested switch'when-"the two-way switch-lain second position-ion decreasing the negative-bias of the second Thyratron to render it conducting. 6. A machine for testing switches having fixed contacts and a movable contact actuated into,

engagement with the fixed contacts by fiuid pressure and having a pressure fluid chamber witha pressure fluid inlet, said machine comprising a workholder for receiving the switch, means for applying fluid pressure to the switch to cause '2'0 iventing operation or -the second Thyratron when the movable contact to engage the fixed contacts,

cluding three sets of normally closed relay contacts in series and opened by energization respectively of magnet coils of first, second and third relays, said coils being connected respectively in parallel with said first, second and third indicators, first, second and third two-way switches each having first or normal positions engaging a first contact and second positions engaging a second contact, means for causing the first switch to move to second position upon attainment of a certain lower pressure of fluid applied to the tested switch, for causing the second switch to move to second position upon attainment of a certain intermediate pressure, and for causing the third switch to move to second position upon attainment of a certain higher pressure, connections from the first contacts of said first, second and third switches, respectively, to the nongrounded ends of the grounded resistances with which the grids of the first, second and third Thyratrons are respectively connected, a connection from the other fixed contact of the tested switch to the first switch, a connection from the second contact of the first switch to the second switch, a connection from the second contact of the second switch to the third switch and a connection from the second contact of the third switch to the non-grounded end of the grounded resistance connected with the grid of the fourth I Thyratron.

engagementwiththe-fixed contacts byi'lfluidipitesy =sure=andihavinga pressure:fiuidrchamben witlr'a pressure ifiuid ginlet, said machine lcomprising -apparatus for connecting: saidinlet. uwithza pres,- sure'fl-ui'd sources-a fluid pressureservorconnected by the apparatus with: the: switch-I chamber-sand having a displaceable member whiclrisniovedlin =-accoi'-dance-with-pressure in the switch chamber, a plurality of two-way switches having firstn or normal positions and :actuated I by saidtqmember successivelyinto their respective second positions "as pressure increases, a plurali'tyof electrically operated indicators -respec'ti vely "for. indicating lowest "to highest pressure ranges-when'the tester! switch =closes',- the number of said, indicators exceeding by one the numb er :oftwoway switches,

*a current source, aplurality of "'Thyratrons respectively 'for connecting the :ind'icaitorswvith the current source, a plurality of relays' equalin number to the number or two-way switches-and *each having -a "magnet coil and normally-closed -con-tacts which are opc-ned'whenthemagnetcoil i's energized, said magnet coils being 'in parallel with those indi'catorsare used respectively to indicate pressurerangeslower than the highest, grid bias controlling resistance net-works associated with the Thyratrons and each normally grid-biasing the associated Thyratron for non-conduction, a first short circuit for a portion of the net-work associated with that Thyratron which, when conductive, passes current to the indicator of the lowest range of pressure in which the test switch contacts close, said first short circuit including, in series, all of the normally closed contacts of the relays, the closed contacts of the tested switch and the contacts, in normal or first position of that two-way switch which would have been actuated had the test switch closing pressure been higher than the lowest pressure range, said first short-circuit causing such change in bias of said first specifically mentioned Thyratron that it passes current to the indicator of lowest pressure range, a second short circuit for a resistance of the net work associated with a second Thyratron which when conducting, passes current to the indicator of an intermediate pressure range, said second short circuit including in series all of the normally closed contacts of the relays, the closed contacts of the tested switch and the contacts in second position, of that two-way switch first to be operated by the fluid pressure actuated member and the contacts, in first or normal position, of that twoway switch second to be operated by said members if the tested switch closing pressure had been higher than the intermediate pressure range, said second short circuit causing such change in thebias of said second Thyratron as to cause it to pass current to the indicator of the intermediate pressure range, a short circuit fora resistance of the net work associated with the Thyratron which, when conductive, passes current to the indicator of highest pressure range, said last mentioned short circuit including in series all of the normally closed contacts of the relays, the closed contacts of the tested switch and all of the two-way switches in their second positions, said last mentioned short circuit causing such change in the bias of the last mentioned Thyratron as to cause it to pass current to the indicator of the highest pressurev range, the operation of the indicator of the pressure range, other than the highest, within which the tested switch closes being accompanied by energization of the relay magnet coil in parallel with that indicator,

115v whereby the contacts of that relay open and no other resistance short circuit can be completed although the pressure upon the displaceable member should increase after the tested switch contacts close, in consequence of which no Thyratron can become conductive other than the one which had passed current to the indicator of the pressure range within which the tested switch closes.

.8. A machine-for testing switches having acase providing a pressure fluid chamber and a pressure fluid inlet, fixed contacts, terminals connected therewith and a movable contact actuated into engagement with the fixed contacts by fluid pressure, said machine comprising a work holder for receiving the switch with its terminals extending from one side of the holder and its pressure inlet in response to motion of the head relative to the head contacts when aswitch to be testedis present upon the holder, a device for connecting the switch chamber with a fluid pressure source and having a nozzle for making connection with the pressure fluid inlet of the switch and means under control by said controller when actuated for causing the device to move to apply its nozzle to said pressure inlet of the switch.

FLOYD J. Foos'r. DON RANDALL BURK. RUPERT c. WI-IELCI-IEL.

REFERENCES CITED The following references are of record in the file of this patent:

I UNITED STATES PATENTS 

